Although children don’t yet understand what words mean, they may stop doing something when a parent or caregiver says “no.” Even if they stop, this does not mean that they understand that something they are doing is wrong or that they have learned that a certain behavior is unacceptable. They might try the same thing again later, and this normal response shows a healthy desire to explore.
Shelov, S. P. (Editor-in-Chief). (2004). Caring for Your Baby and Young Child: Birth to Age 5. The American Association of Pediatrics. Revised edition. New York: Bantam Books.